Johnson 70 (1997) VRO

I have recently bought (with the boat) a Johnson 70 (1997) , however, after maybe 7 hours it threw a con rod ! ??. Even though it was dealer serviced before my purchase ???I have spoken to the dealer but I would probably get more response from talking to a wall !

I have stripped the powerhead and the problem was due to water damage on No3 cylinder and a good replacement powerhead has been sourced ???.. it is assumed that the boat took on rain water at its sea mooring which allowed the lower engine cowl to go below water level !.....I am guessing that all this happened to the last owner just before the boat came up for sale, and it was stood for 6 months before I purchased it???.. TBH the engine sounded very sweet right up until it threw the rod ???..so now you have the important history.

The document history shows the VRO pump (I assume VRO2) had been disconnected due to the engine smoking badly and the very same dealer had diagnosed the pump as having a suspected faulty oil diaphragm and delivering too much oil. It was changed to run on 50:1 premix and it ran OK.

I have looked at the manual and the VRO pump is controlled by pulses from No3 cylinder. As No3 would have had little or no compression and the inlet reed vales were rusted in the open position could this have caused the issues with the VRO pump oil delivery ?

When fitting the replacement powerhead I was thinking of going back to using the VRO ???. Or is premix a better option

Re: Johnson 70 (1997) VRO

gpsguru said:

I have looked at the manual and the VRO pump is controlled by pulses from No3 cylinder. As No3 would have had little or no compression and the inlet reed vales were rusted in the open position could this have caused the issues with the VRO pump oil delivery ?

When fitting the replacement powerhead I was thinking of going back to using the VRO ???. Or is premix a better option

Click to expand...

IMHO, No and yes. If water ingestion was a factor, more than likely, the piston rings had rust on them and caused the failure of #3.

I have NEVER had an issue with oil injection systems on OMC's. That is with cautions:

They need to be maintained. That includes:

1. Yearly evacuating of oil to make sure no water is present.

2. Inspect hoses and clamps.

3. Make sure warning horn is working.

The OMC "VRO" has been wrongly blamed for thousands of engine failures.

With a little maintenance, it is a good system.

Re: Johnson 70 (1997) VRO

I have to agree with DJ! The VRO system is an excellent system as long as it is maintained like any other working part.
Sorry to hear about a bum motor but it sounds like you have it in order and will have an even better motor when it is back together.
In 25 years on my 115 HP OMC I'm on my third power head and second VRO (fuel side failure on the first one 3 years ago) and have thousands of hours of happy boating! Maintenance is the key and twelve months a year of boating helps my mental state as well!

Happy Boating and Good Luck!!

Re: Johnson 70 (1997) VRO

Sorry to hear that you have had such a catastrophic failure.
The water issue could come from the fuel. If the motor did not have a water separation filter in the fuel line then water could have entered the motor and it usually gravitates to the lowest cylinder. If a motor is left to sit without running, water gets into the bearings and damage ensues. All of my larger motors are equipped with a water trap filter.
This damn ethanol is largely to blame. Use Stabil Marine and the filter to minimize this problem.
I would recommend staying with the 50:1 as the VRO systems are suspect. Not at all as reliable as a gear driven pump. In fact the only reliable pump system that I have found is the Suzuki and they need to be checked periodically. Incidentally the oil of my preference is Penzoil blend. I have been using this on all motors that I run and those of my friends that use it say it is their preference. Less smoke and no troubles.
Good luck with the rebuild, you should have a better motor as a result.
Oh, and keep your carbs clean.